the military conflicts between powers likely to happen in such places to gain the strategic control over a high possible custom, revenue collection and control of a strategic trade gateway.

Trade corridors in frontier zones often produced intense political struggles because they controlled both:

economy,and sovereignty.

Among different stories, a unique Mangar folklore stands out with a story about an assassination of the Mangar chieftain by the Tibetan subject, the reason being the imposition of high toll tax by the fort administration, it also tells a tale of the lady queen having her revenge by serving the poisoned wine during the death ritual ceremony of her husband Mangar chieftain, hence the place remembered as "the land with thousand corpses.

And if Mangardzong stood near an eastern Himalayan trade approach connected toward Chumbi Valley, then it may once have been part of a much larger network of:

hill polities,
caravan economies,
and frontier diplomacy.

At that point, the folklore stops sounding like an isolated legend and starts sounding like a fragmented memory of a lost frontier power structure.

the main question regarding the Mangardzong arises so,

why are so many of the administrative forts named Mangardzong found in this region and Himalayan frontier area?

during that time which big power or empire had its political and administrative influence over the Sikkim and Darjeeling area and over the small tribal republics before the Chogyals and British?

the fact found in the various old documents also shows that different limbu Subbas of limbuan had remained under kipat system of the Sen kingdom before Gorkha invasion.

the history of Mangar tribe in Sikkim, Darjeeling, Kalimpong, Mirik and Bhotan region may be Still alive in a different spelling form of a distorted version referring to term MANGARDZONG, and also in form of fort ruins and folklores, but it needs more deep political and historical and research.

It is encouraging to know that an educated man is now doing his best to document the history of the Mangars and create institutions to preserve their history and heritage.
I hope this is an inspiration to others to document the history and heritage of several native tribes who contributed to the democratization of society